[hfjbuis]

I do threading using a stepper (Nema23 2Nm) mounted on the spindle and control it as C-axis. This works fine and you can do any pitch threading. No need to have a box full of taps. For most jobs, 2 Nm is strong enough, can't even run it at max speed otherwise deflection of the part will be to much. And for the larger threads, just reduce speed and cutting depth. Takes i bit longer but who cares, it runs automatically. I recently changed to Nema24 4Nm because i had trouble threading ER32 (M40) on Cr42Mo4 steel. Works even better though i found out today the problems where caused by the power supply (now outputs only 14 Volts). If you have a stepper mounted on the spindle, you can do other cool things like broaching, knurling and grinding drills and end mills. It turns your lathe in a very versatile tool.

[ZeroBacklash]

I do threading using a stepper (Nema23 2Nm) mounted on the spindle and control it as C-axis. This works fine and you can do any pitch threading. No need to have a box full of taps. For most jobs, 2 Nm is strong enough, can't even run it at max speed otherwise deflection of the part will be to much. And for the larger threads, just reduce speed and cutting depth. Takes i bit longer but who cares, it runs automaticaly. I recently changed to Nema24 4Nm because i had trouble threading ER32 (M40) on Cr42Mo4 steel. Works even better though i found out today the problems where caused by the power supply (now outputs only 14 Volts). If you have a stepper mountedon the spindle, you can do other cool things like broaching, knurling and grinding drills and end mills. It turns your lathe in a very versatile tool.

That's amazing to hear I intended to do that (mounting a stepper on the spindle) but I was a bit sketical of the rpms its would achieve like 3000 rpm or so for regular facing operatiosn etc..So I decided to focus on a brushed or bldc servo with a built in tach. But you have opened up a good a new avenue, would the stepper acheive rpms of 3000?

[hfjbuis]

I use the stepper only as C-axis and it is engaged by a lever. For all other turning tasks, I use the original motor. I mounted the motor on top of the lathe, but the next build i will place it in the gearbox and use the tumbler lever (lever for changing spindle direction)... for engaging.
For drawings, information and photo's, look at:Welkom op www.mwt.messageboard.nl

I don't think you can run this large steppers that fast and still having some useful torque left. You could mount a closed loop stepper. I have never tried them but the specs look pretty good. Just for information, the first i found on google
https://www.banggood.com/High-Speed-...r_warehouse=CN

[hfjbuis]

Multi-pass threading will be implemented in the august release of the software.